What Is Organic Chemistry?: Crash Course Organic Chemistry #1

Summary

Crash Course Organic Chemistry introduces the study of carbon-based molecules, which are ubiquitous in nature and essential to modern life. The course delves into organic chemistry's history, starting from ancient medicinal plant uses to the modern synthesis of compounds like urea. It covers various ways to represent molecules, including Lewis structures, condensed formulas, and skeletal formulas. The video also highlights the importance of functional groups and heteroatoms in organic compounds, emphasizing their role in daily life from fabric dyes to caffeine in coffee.

Takeaways

• 🌟 Chemistry is the science of everything, with all matter composed of atoms that interact in various ways.
• 🔍 Organic chemistry specifically focuses on molecules containing carbon atoms, which can form diverse and complex structures.
• 📚 The term 'organic chemistry' was coined by Jöns Jacob Berzelius and initially referred to compounds derived from living organisms.
• 🌿 Ancient civilizations used organic compounds, such as those found in plants, for medicinal purposes and dyeing fabrics.
• 💧 Urea, a compound found in urine, was historically used as a dye mordant to enhance and preserve fabric colors.
• 🚀 Friedrich Wöhler's synthesis of urea from an inorganic compound in 1828 marked the beginning of the modern organic chemical industry.
• 📝 Lewis structures are used to represent the bonding and electron pairs in organic molecules, providing a detailed view of their composition.
• 📐 Condensed structural formulas and skeletal formulas offer simplified ways to depict organic molecules, focusing on key structural elements.
• 🌈 Heteroatoms, or atoms other than carbon and hydrogen, play a significant role in organic compounds, often determining their reactivity and function.
• 🌐 Organic compounds are ubiquitous in modern life, from the caffeine in our coffee to the polymers in our electronic devices.

Q & A

What is the focus of the Crash Course Organic Chemistry?

The focus of the Crash Course Organic Chemistry is on the study of molecules that have carbon atoms, which often bond to themselves to form various compounds.

Why is carbon significant in organic chemistry?

Carbon is significant in organic chemistry because it has four valence electrons, allowing it to form four bonds, which leads to the creation of diverse and complex organic compounds.

What was the historical belief about the origin of organic compounds?

Historically, it was believed that organic compounds could only be harvested from living things and not synthesized artificially.

Who is credited with the discovery that organic matter could be synthesized from inorganic compounds?

German chemist Friedrich Wöhler is credited with the discovery that an inorganic salt, ammonium cyanate, could be used to make urea without a living organism.

What is the role of urea in fabric dyeing?

Urea acts as a fabric dye mordant, enhancing the color and longevity of the dye by forming a chemical bridge between the dye molecule and the fabric.

What is the significance of Wöhler's discovery in 1828 in the context of organic chemistry?

Wöhler's discovery in 1828 marked the starting point of the modern organic chemical industry, demonstrating that organic compounds could be synthesized from inorganic materials.

What are the different ways to represent organic molecules?

Organic molecules can be represented through Lewis structures, condensed structural formulas, and skeletal formulas or line-angle formulas.

Why are skeletal formulas useful in organic chemistry?

Skeletal formulas are useful because they simplify the representation of organic molecules by removing explicit hydrogen atoms and carbon atoms, focusing instead on the bonds and functional groups.

What are heteroatoms in organic compounds?

Heteroatoms are atoms in organic molecules other than carbon and hydrogen, such as nitrogen, oxygen, sulfur, and halogens.

What is the importance of functional groups in organic chemistry?

Functional groups are parts of organic structures that include non-carbon atoms or have double and triple bonds, and they are where most of the interesting chemistry occurs.

How did the ancient Romans utilize urea?

The ancient Romans used urea, a component of urine, as a dye additive, particularly for indigo dye, to enhance the color and make the dye last longer.

Outlines

00:00

🌟 Introduction to Organic Chemistry

Deboki Chakravarti introduces the course on organic chemistry, emphasizing its relevance to everything from stars to our bodies. Organic chemistry focuses on carbon-containing molecules, which can form diverse structures due to carbon's ability to bond with itself. The course will explore the historical development of organic chemistry, starting from the mid-1800s, and the evolution of its definition to include both naturally occurring and synthetic compounds. The importance of understanding molecular structures and reaction mechanisms is highlighted, with the promise of uncovering new reactions and compounds throughout the series.

05:06

📚 Organic Chemistry Structures and Representations

This section delves into the various ways of representing organic compounds, starting with Lewis structures that detail atomic connections and electron pairs. It explains how to draw such structures for propane, ensuring each carbon atom achieves an octet. The video then simplifies this representation to condensed structural formulas and skeletal formulas, which are more practical for chemists. The importance of heteroatoms and functional groups in organic molecules is introduced, with examples like aspartame and retinal. The episode concludes with a teaser for upcoming lessons on nomenclature and the historical use of urine in dyeing fabrics.

Keywords

💡Organic Chemistry

Organic chemistry is the branch of chemistry that focuses on carbon-containing compounds. In the script, it is highlighted as the study of molecules that have carbon atoms, which are capable of forming complex structures due to their ability to bond with themselves and other elements. The video emphasizes that organic chemistry is not just about natural compounds but also includes synthetic ones, making it relevant to a wide range of applications from pharmaceuticals to materials science.

💡Carbon

Carbon is a key element in organic chemistry due to its unique ability to form four covalent bonds, allowing it to create a vast array of complex molecules. The script mentions that carbon's valence electrons enable it to form chains or rings, which are fundamental to the structure of organic compounds. Examples given include dodecane, anthracene, and estradiol, showcasing the diversity of carbon-based molecules.

💡Valence Electrons

Valence electrons are the electrons in the outermost shell of an atom that are involved in chemical bonding. In the context of the video, carbon's four valence electrons are crucial for its ability to form stable bonds, which is the basis for the vast diversity of organic compounds. The script uses this concept to explain how carbon can form chains and rings, fundamental to understanding organic chemistry.

💡Lewis Structure

A Lewis structure is a representation of the electrons in a molecule, showing how atoms are bonded and where lone pairs of electrons are located. The script uses Lewis structures to illustrate how to depict the bonding in simple organic molecules like propane. This visual tool is essential for understanding the structure of organic compounds and predicting their reactivity.

💡Condensed Structural Formula

A condensed structural formula is a simplified way of representing organic molecules where hydrogen atoms bonded to carbon are grouped together, rather than each being drawn individually. The script introduces this concept as a way to simplify the depiction of organic molecules, making it easier to focus on the structure and function of the compound without the complexity of a full Lewis structure.

💡Skeletal Formula

A skeletal formula, also known as a line-angle formula, is a further simplification of organic structures where carbon atoms and their attached hydrogens are omitted, leaving only the bonds and non-hydrogen atoms. The script explains that in skeletal formulas, the bends or ends of lines represent carbon atoms, and this representation is used to focus on functional groups and heteroatoms, which are key to understanding the chemistry of organic molecules.

💡Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The script mentions that functional groups are where 'all the cool chemistry happens,' emphasizing their importance in determining the properties and reactivity of organic compounds. Examples from the script include the complex structures of estradiol and the role of functional groups in the color of beets.

💡Heteroatoms

Heteroatoms are atoms within organic molecules that are not carbon or hydrogen. The script explains that these atoms, such as nitrogen, oxygen, or sulfur, can be part of functional groups and significantly influence a molecule's properties. The inclusion of heteroatoms in skeletal formulas helps chemists focus on the parts of molecules that are crucial for understanding their reactivity and function.

💡Molecular Formula

A molecular formula provides the exact number of each type of atom in a molecule. The script uses the example of propane, with the molecular formula C3H8, to illustrate how this information differs from the structural formula, which shows how the atoms are bonded. Understanding molecular formulas is essential for identifying and characterizing organic compounds.

💡Urea

Urea is a compound that is naturally found in urine and has historically been used as a dye mordant to fix colors in fabrics. The script recounts the historical use of urea in dyeing, including the Roman practice of selling urine for this purpose. The discovery by Friedrich Wöhler that urea could be synthesized from an inorganic compound marked a significant shift in the understanding of organic chemistry, as it demonstrated that organic compounds could be made without living organisms.

Highlights

Chemistry is the science of everything, including stars, computer hard drives, desks, and our bodies, all composed of atoms in various arrangements and reactions.

Organic chemistry focuses on molecules containing carbon atoms, which can form diverse compounds due to carbon's ability to bond with itself.

The term 'organic chemistry' originated from the study of compounds extracted from living organisms, as coined by Swedish chemist Jöns Jacob Berzelius.

Before the modern era, it was believed that organic compounds could only be sourced from living things, not synthesized.

Urea, a compound found in urine, was historically used as a fabric dye mordant, enhancing dye color and longevity.

Ancient Romans sold urine for fabric dyeing, leading to a government-imposed urine tax.

German chemist Friedrich Wöhler's synthesis of urea from an inorganic salt in 1828 marked the beginning of the modern organic chemical industry.

Organic chemistry now encompasses the study of carbon-containing compounds, including those synthesized and those found in nature.

Carbon's ability to form four bonds is central to understanding the structure of organic molecules.

Lewis structures are used to illustrate the bonds and lone pairs of electrons in organic molecules, providing a detailed view of molecular connectivity.

Condensed structural formulas simplify the representation of organic molecules by grouping hydrogens with their bonded carbons.

Skeletal formulas or line-angle formulas further simplify organic structures by omitting carbon and hydrogen atoms, focusing on the bond framework.

Functional groups, which include non-carbon atoms or multiple bonds, are key to the chemical reactivity of organic molecules.

Heteroatoms, or atoms other than carbon and hydrogen in organic molecules, play a significant role in the molecule's properties and reactions.

Organic compounds are integral to everyday items, from the caffeine in coffee to the retinal in our eyes that enables vision.

Advances in polymer chemistry have led to the development of conductive plastics, contributing to the creation of lightweight electronic devices.

The color in many natural and man-made items, such as beets and fabric dyes, is due to the presence of organic compounds.

The course will delve into the nomenclature of organic molecules, providing a systematic way to name these diverse compounds.

Transcripts

Hi! I’m Deboki Chakravarti and welcome to Crash Course Organic Chemistry!

The science of chemistry is pretty incredible because it’s the science of… everything.

Stars and computer hard drives and desks and our bodies are all made up of different arrangements of atoms that are bonded together, breaking apart, or reacting with each other all the time.

We already did a Crash Course about the wonders of general chemistry.

So this course will focus on just a slice of that pie, because we’re talking about organic chemistry.

And organic chemistry is the study of molecules that have carbon atoms.

With four valence electrons, carbon often catenates, which means it bonds to itself.

So it forms lots of different compounds.

You can get long chains of carbons and hydrogens, like dodecane, or rings of carbons like anthracene, or complex structures with multiple rings and other atoms like the steroid estradiol.

You might think that the whole focusing-on-carbon thing would rule out a lot of the universe -- and it does rule out things like glass, rocks, minerals, and gems other than diamonds.

But organic chemicals are pretty much everywhere!

Over these 50 episodes, we’ll discover new reactions, new compounds, and new methods to understand them.

And all of these discoveries didn’t just appear in a chemistry lab notebook overnight.

They’re the result of centuries of hard work isolating chemicals, trying to figure out what they do, and stumbling upon happy accidents that led to revolutionary ideas.

A big part of understanding organic chemistry is grasping the logic behind everything from molecular structures to chemical reaction mechanisms.

Even though these kinds of problems can feel overwhelming, treating them like a puzzle can help us make sense of them.

So let's start our story with the birth of modern organic chemistry, which begins right around the mid-1800s.

[Theme Music]

Plants like willow, ephedra, and poppies were known by ancient civilizations to have medicinal benefits, but they had no idea why.

In the early 1800s, there was a breakthrough in understanding their medicinal properties, and people began to extract therapeutic chemicals from them.

Today, we know that these plants contain medicinal organic molecules like salicylic acid, ephedrine, and morphine.

Organic means “derived from living things,” and the term “organic chemistry” was coined by the Swedish chemist Jöns Jacob Berzelius, who discovered several elements and came up with the modern chemical symbols that we use today.

At that time, organic chemistry referred to the study of chemical compounds extracted from living things.

We thought that organic compounds could only be harvested from living things, but not made.

That’s why we used to dye our fabrics beautiful colors using organic plant materials, like flowers and dirt… with a little help from our own urine.

Urea is the main nitrogen-containing part of urine that comes from our body’s metabolic breakdown of proteins.

But it’s also a great fabric dye mordant, which is a chemical that makes the dye last longer and often enhances the color.

This is because urea can form a chemical bridge between the dye molecule and the fabric, and it shields the dye from fading.

There’s evidence that urea was used by ancient civilizations as a dye additive, particularly for indigo dye.

The same dye that makes our jeans blue!

In ancient Rome, people would even sell their urine to dyers to make some money.

It was such a big business that the government even passed a urine tax to get a cut of the profits.

If you’ve ever tie-dyed a shirt, the colored dye solution probably had urea in it too.

But don’t worry, since we’ve moved beyond the “get every chemical from living things” days of organic chemistry, it’s not derived from urine.

This urea is synthesized from an inorganic compound.

And for that, we can thank German chemist, Friedrich Wöhler.

He was a rock collector and is credited with being the first person to isolate the elements yttrium, beryllium, and titanium -- and the first person to discover organic matter on meteorites.

But he’s most well known for his discovery that an inorganic salt, ammonium cyanate, could be used to make urea without a living organism.

Wöhler’s discovery in 1828 is considered the starting point of the modern organic chemical industry.

And today, organic chemistry is defined as the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds.

This definition includes chemicals extracted from living things, but also man-made polymers, like plastics.

Throughout this course, we need to remember this one simple thing: organic chemistry is carbon-centric.

Carbon is the key atom in all these molecules, and carbon atoms do some very predictable things, like make four bonds.

Keeping this in mind, there are several different ways we can draw organic compounds.

One way to represent organic molecules is with a Lewis structure, like the ones we drew in Crash Course General Chemistry.

Lewis structures illustrate what atoms are connected and they show all of the bonds and lone pairs of electrons in a molecule.

For example, propane is a common fuel for home heating and barbeque grills.

And it’s a simple organic compound.

Because we haven’t learned how to name compounds yet, I’m just going to say that propane’s molecular formula is C3H8, so it has 3 carbon atoms and 8 hydrogen atoms.

A molecular formula tells us the atoms web have and how many of each atom there is, but it doesn’t tell us what’s bonded to what.

For that, we’ll need a Lewis structure.

As I mentioned earlier, organic molecules can make carbon chains, so let’s start by connecting all 3 of propane’s carbons in a straight line.

Then, knowing that carbon atoms prefer to make four bonds, we can add enough hydrogen atoms around each carbon so that they have four bonds.

Lastly, we need to check that we’ve accounted for all 3 carbons and 8 hydrogens in propane’s structure.

And, more importantly, we need to make sure each carbon has 8 electrons around it—an octet.

Remember that each bond represents 2 electrons, so 4 bonds per carbon is 8 electrons.

So we’re good!

Writing Lewis structures for small carbon chains isn’t too bad.

But drawing a bigger organic structure that shows all of the bonds, hydrogen atoms, and electrons can start to get complicated.

And, let’s be real, we’re busy chemists.

We don’t have the time to draw every structure like this every time.

So the first simplification we can make is called a condensed structural formula, where we group all of the hydrogens together next to the carbons they’re bonded to, instead of drawing each one separately.

That’s better, but it’s still a bit crowded.

So we can simplify the structure even more by removing all the carbons and their attached hydrogens.

This leaves behind a skeleton of lines representing bonds, which is why this is called a skeletal formula or line-angle formula.

In skeletal formulas, carbons are the bends or the ends of the lines.

And hydrogens aren’t shown because carbon atoms in most organic compounds have 4 bonds, so the number of hydrogens needed to give each carbon 4 bonds is implied.

We can take these drawing shortcuts for all kinds of organic molecules, no matter how complicated or simple they are.

For example, let’s look at a straight chain of eight carbons with the molecular formula C8H18.

That’s octane, by the way, but we’ll get to naming in a later video.

The Lewis structure of octane looks like this, the condensed structural formula looks like this, and the skeletal formula looks like this.

And you can see that, unlike the Lewis structure, the skeletal formula uses zig-zag lines to represent bonds, because we need those bends to see how many carbon atoms are in the structure.

One long straight line basically wouldn’t tell us anything!

We’ll need to move between these structural representations a lot throughout this series.

So, given the skeletal structure for iso-octane, an important component in gasoline, we’ll need to know it translates to this condensed formula, and this Lewis structure.

But the thing is, organic chemistry isn’t just carbon and hydrogen atoms.

We have a whole periodic table of elements!

We’ve even got a poster!

Though there are a few main ones that are commonly a part of organic compounds.

These atoms in organic molecules other than carbon and hydrogen are called heteroatoms.

We always show heteroatoms with the attached hydrogens in the skeletal formula, like this one for the artificial sweetener aspartame.

Also, it’s sometimes helpful to show the lone pairs of electrons on heteroatoms, because it’ll help us think about chemical reactions.

Skeletal formulas make it easier for us to focus on the parts of an organic structure that are non-carbon atoms or have double and triple bonds.

These parts are called functional groups and that’s where all the cool chemistry happens!

We’ll be dealing with a lot of these skeletal structures or other depictions of organic compounds, but it’s also important to remember that these chemicals are real things that we use on a daily basis.

Aspartame, which I just mentioned, is in the little blue sugar packets that we can add to our coffee.

And this cup is already full of organic compounds that give coffee its taste and smell and most importantly, the caffeine that helps us wake up in the morning!

The whole reason anyone can see this video in the first place is an organic chemical called retinal, a molecule in our eyes that’s responsible for turning visible light into nerve signals.

And, not to mention, most video screens and computer equipment have lots of organic polymers.

One important breakthrough in polymer chemistry in the 1970s was how to make plastics conduct electricity.

These special kinds of polymers are responsible for lightweight laptops, tablets, and phones we carry around, because plastics are a lot lighter than metals.

Also, light-emitting polymers are responsible for full color displays.

These light-emitting polymers behave almost like metals but change colors with different amounts of electricity.

Plenty of natural things like flowers, fruits, and vegetables are colored because of organic compounds too.

Like, beets are high in betanin, a dye that gives them a lovely purple color.

Some people don’t metabolize betanin so it turns their urine and feces purple.

It’s also a great fabric dye.

So to bring this all full-circle, organic compounds give color to a lot of the foods and other things we see every single day, whether they’re fixed with urea or not!

I hope you’re just as excited as I am about how diverse organic compounds are.

We’re going to learn so much together!

But in this episode, we talked about:

The origins of modern organic chemistry

How to write Lewis structures, condensed structures, and skeletal formulas

A brief introduction to functional groups and heteroatoms

And how Romans used to soak their fabrics in urine dye to make them pretty colors

Next time, we’ll work on nomenclature and what to call these organic molecules!

Thanks for watching this episode of Crash Course Organic Chemistry.

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